It's sad but they would use gas chambers (and call them showers) to kill them or they would round them up and just shoot a good number of them at a time. I hope this helps!
The hardships for Moving west were that you could run out of food or supplies. But there motivations were high becuase they needed more land becuase the population was growing and there wasn't enough room for everybody in their towns.
The Allies held deception exercises that had the Germans convinced that the invasion would occur in the Pas-de-Calais, while the real target was Normandy (the actual beach names given to the operation were Utah and Omaha.) Even when the Germans saw the Allied fleet coming at Normandy, they were convinced that Normandy was the deception. If they responded to Normandy, then Pas-de-Calais would be defenseless.